A number of reasons now exist in the fields of both medicine and poultry husbandry, among others, which call for the injection of various types of avian eggs with various substances for particular reasons. In the field of medicine, eggs have typically been used to incubate certain vaccines which have medical applications.
More recently, as the field of poultry embryology has become more advanced, it has been discovered that the addition of various substances to the embryo or to the environment around the embryo within an avian egg can have beneficial effects on the growth of the subsequently hatched chick, the prevention of disease in hatched chicks, the percentage hatch of large numbers of incubated eggs, and the physical characteristics of hatched poultry. Additionally, more recent studies indicate that certain types of vaccination which could heretofore only be carried out upon either recently hatched or fully mature poultry, can now be successfully accomplished while the chick is still embryonated.
Depending upon the purpose for which the egg is being treated, the location of injection will vary. For certain purposes, the substance to be injected into the egg needs to be delivered to the amniotic fluid near the small end of the egg, for other purposes the material needs to be delivered to the air sac end of the egg, and there may even arise occasions when a substance should be delivered to the embryo itself. Nevertheless, where eggs are being incubated to produce live poultry, care must be taken to avoid injuring the embryos during the injection and delivery of fluid substances. Individual eggs, however, can vary widely in size with accompanying associated differences in the distance between the shell and the location to which delivery of a fluid substance is desired. These differences can complicate the task of consistently supplying a desired substance to a particular location within each of a large number of eggs at a fast rate of speed.
One traditional method of injecting eggs is injection by hand. Although skilled operators can inject eggs by hand with some success, the speed and accuracy of the process is limited. Additionally, hand injection of eggs, even by skilled operators, cannot always guarantee the continuous repeated precision delivery of materials to a desired particular location within each egg. Presently, there exist no widely used or practical techniques or methodologies for high speed precision application of active substances into eggs.
Similarly, an alternative technique for treating poultry to obtain desired results has been hand injection of very young--typically day-old--chicks. As in the hand injection of eggs, speed and precision are limited. Furthermore, injection so soon after hatch places significant stress on the young chicks.
In addressing these problems, several automatic devices have been disclosed for injecting eggs. These include patents issued to Sandhage, U.S. Pat. No. 3,377,989, and to Miller, U.S. Pat. Nos. 4,040,388 and 4,469,047. Sandhage discloses a hand operated egg injection device for injecting a few eggs at the same time, but does not disclose any method or system for handling large numbers of eggs quickly and accurately. Miller '388 discloses an apparatus for injecting the smaller ends of eggs and resealing the holes produced, and Miller '047 shows a somewhat different device for injecting eggs from their larger, air sac ends. Both Miller patents disclose automated techniques, but apparently no actual devices based on the Miller disclosures have met with much market success, for whatever reasons.
Furthermore, none of these devices lift eggs of varying sizes by pulling them towards an injection device. Instead, all either push eggs toward an injection device or fail to move them at all. Given the relatively fragile nature of eggs, pushing them from one direction while puncturing them from the opposite direction can cause an economically significant increase in breakage rates.
Finally, all of these devices disclosed in these patents puncture eggs with the same instrument with which they deliver the fluid substances. Accordingly, various types of precise needles which may not be rigid enough to puncture an egg shell cannot be used in these devices. Alternatively, if such devices are equipped with needles large enough and rigid enough to puncture the eggshell, such needles may not provide the precise delivery of fluid--both as to location and amount--which more delicate needles can provide. Furthermore, the punching process will dull the beveled edge necessary for membrane penetration.
Accordingly, it is an object of this invention to provide an automatic egg injection machine which can simultaneously inject a plurality of eggs of varying sizes and deliver injected fluid substances to the same particular location with each egg, regardless of the size of the egg.
It is a further object of this invention to provide means for lifting a plurality of eggs from their upwardly facing ends rather than pushing them from the portions which rest on a tray or other holding device.
It is another object of this invention to provide a device and a method for automatically innoculating eggs with fluid substances while concurrently transferring the eggs from one position to another, such as from an incubation setting tray to a hatching tray.
It is a further object of this invention to provide a device which positions an egg and an injection needle in a fixed relationship with respect to one another in order to provide accurate and precise injection and delivery of fluid substances to a desired location within eggs of various sizes, regardless of the various sizes of the eggs.
Finally, it is an object of this invention to provide a device in which the functions of perforating the eggs and delivering fluid substances are carried out by two different tools or mechanisms so that each can be tailored to perform the intended task in the best possible manner.